Incident took place as US, other world powers met with Iran to negotiate nuclear deal

An Iranian military observation aircraft flew within 50 yards of an armed U.S. Navy helicopter over the Persian Gulf this month, sparking concern that top Iranian commanders might not be in full control of local forces, CNN has learned.

The incident, which has not been publicly disclosed, troubled U.S. military officials because the unsafe maneuver could have triggered a serious incident.

It also surprised U.S. commanders because in recent months Iranian forces have conducted exercises and operations in the region in a professional manner, one U.S. military official told CNN.

"We think this might have been locally ordered," the official said.

The incident took place as the U.S. and other world powers meet with Iran in Switzerland to negotiate a deal limiting Tehran's nuclear program. At the same time, Iran has been active in supporting proxies in several hotspots in the Persian Gulf and neighboring regions.

The Navy MH-60R armed helicopter was flying from the deck of the USS Carl Vinson on a routine patrol in international airspace, the official said.

An unarmed Iranian observation Y-12 aircraft approached. The Iranian aircraft made two passes at the helicopter, coming within 50 yards, before the helicopter moved off, according to the official.

The official said the helicopter deliberately broke off and flew away in a 'predictable' manner so the Iranians could not misinterpret any U.S. intentions.

The Navy helicopter was in radio contact with the ship during the encounter, but there was no contact between the two aircraft and no shots were fired.

The Navy crew took photos of the incident but the military is not releasing them.

The U.S. administration is considering a potential demarche protest against Iran, the official said.

CNN has reached out to Iranian officials but has not received a response.

This type of Iranian observation aircraft generally operates over the Gulf several times a month. But after the recent incident, U.S. naval intelligence did not see it again for two weeks, leading to the conclusion that the incident may have been ordered by a local commander who was then reprimanded by higher-ups.

The Pentagon has noted for the last several years that most encounters with the Iranian military at sea or in air are conducted professionally, but that some missions run by Iranian Revolutionary Guard Corps forces have been too aggressive against U.S. forces in the area.

The U.S. military's concern has been that one of these incidents could escalate into a military encounter.

This incident "might have been buffoonery" the official said, but there is always a risk from such actions.

The incident comes as the Navy patrols the Gulf of Aden to watch for Iranian ships the U.S. believes are trying to bring weapons to resupply the Houthi rebels in Yemen. The Navy would share such intelligence with Saudi Arabia, a second U.S. official told CNN.

Former Maryland Gov. Martin O'Malley took a major shot at Hillary Clinton on Sunday, saying the country needs a "new perspective" and "new leadership" in the 2016 election. "Let's be honest here," O'Malley said. "The presidency of the United States is not some crown to be passed between two families."

O'Malley, a Democrat who is considering running for president in 2016, attended the "Politics and Eggs" forum in Bedford, New Hampshire, on Tuesday. The forum gives local business leaders a chance to hear from potential presidential candidates.

O'Malley stopped short of picking on former Secretary of State Hillary Clinton during his stop in New Hampshire.

He made news on Sunday by taking a verbal shot and both Clinton and former Florida Gov. Jeb Bush. On a Sunday talk show, O'Malley said, "The presidency of the United States is not some crown to be passed between two families."

O'Malley knows something about the power of political families. The woman he married, Katie O'Malley, is part of the Curran family, which has included several members of the Baltimore City Council. The family patriarch, Joe Curran, was the state's long-time attorney general and a man instrumental in getting O'Malley started in his political career.

On Tuesday, he stepped back and made no mention of Clinton at all.

O'Malley stuck to his script of talking about middle-class issues, immigration reform and managing with programs like CitiStat. He did comment on the new and controversial religious freedom law signed by Indiana Republican Gov. Mike Pence that critics said allows discrimination against gays and lesbians.

"The wave of anti-gay, anti-lesbian legislation that is sweeping across many states is reprehensible and counter to everything we stand for as a people. It is wrong," O'Malley said.

O'Malley was also scheduled to attend the New Hampshire Young Democrats Social Hour in Nashua, New Hampshire.

O'Malley, who finished his second term as Maryland's governor in January, says he plans to announce a decision on seeking the presidency this spring.

The defense case lasted less than two days, while the prosecution presented more than 90 witnesses over the course of a month.

Federal prosecutors rested their case Monday with grisly testimony about how the bomb Dzhokhar Tsarnaev placed near the marathon's finish line tore through the bodies of 8-year-old Martin Richard and Lingzi Lu, a 23-year-old grad student.

The short presentation in the sensational trial wasn't surprising, given that Dzhokhar Tsarnaev's attorney, Judy Clarke, acknowledged during opening statements that "it was him," referring to her client's culpability.

Testimony ended with an FBI fingerprint investigator who talked about numerous pieces of evidence with Tamerlan's fingerprints and not Dzhokhar's.

Earlier, a computer expert testified about computer searches on Tamerlan's computer -- including gun stores, transmitters, fireworks firing system, detonator and Boston Marathon -- in the weeks before the bombing. Similar searches were not found on Dzhokhar's computer.

Jurors first will be asked to determine whether Tsarnaev is guilty of 30 counts. Because 17 of those counts carry the death penalty as a possible punishment, a second phase of the trial will follow if the jury convicts him.

In the penalty phase, jurors will be asked to weigh aggravating factors, such as the heinousness of the crime, versus mitigating factors, such as Tsarnaev's family history and his youth. He was 19 at the time of the bombings.

Defense strategy focuses on sibling's influence

The defense, which began calling witnesses Monday afternoon, has argued that Tsarnaev, known to friends as Jahar, fell under the sway of his more extremist older brother after their parents moved back to Russia. Jahar Tsarnaev was flunking out of the University of Massachusetts and had lost his financial aid at the time of the bombings.

Prosecutors William Weinreb, Aloke Chakravarty, Nadine Pellegrini and Steve Mellin presented witnesses who told the story of Tsarnaev's alleged scheme with Tamerlan to build and detonate pressure cooker bombs as an act of jihad. The brothers, Muslims of Chechen descent, allegedly sought to kill Americans at an iconic public event to retaliate against U.S. policies they believed harmed and oppressed Muslims abroad.

Prosecutors delved into Tsarnaev's text messages and Twitter posts and showed jurors militant material found in his laptop, phone and iPod. They included writings available online from top leaders of al Qaeda.

They used data mined from a GPS device and store receipts to trace the purchase of the pressure cookers, BBs and ammunition. Jurors saw photos of pressure cooker parts, fuses, Christmas lights and other bombmaking materials found in the Tsarnaev family's Cambridge apartment, where Tamerlan lived with his wife and child.

And they showed security surveillance videos of the brothers in the crowd near the finish line: In one, Dzhokhar Tsarnaev can be seen blending in with the crowd behind the Richard family for four minutes. He appears to slide a backpack off his shoulder near a tree and walk off, glancing over his shoulder. He broke into a run as the bomb went off.

After the surveillance photos were released to the public three days after the bombing, the brothers allegedly embarked on a desperate -- and deadly -- attempt to escape.

Jurors heard from carjacking victim Dun Meng and saw the brothers on convenience store surveillance video shortly before Meng's escape. He can be seen jumping out of his leased Mercedes SUV at a gas pump and running across the screen as Dzhokhar Tsarnaev casually strolls through the store, picking up an armload of snacks.

Prosecutors also used ballistic evidence to link the brothers to the shooting of a campus cop at the Massachusetts Institute of Technology and a gunbattle with police in Watertown.

Tamerlan Tsarnaev, 26, died as a result of that gunbattle. The defendant, allegedly attempting to run down police, instead ran over his brother in the stolen Mercedes.

Jurors also viewed a boat in which Dzhokhar Tsarnaev sought refuge during the ensuing manhunt, which put Boston under a "shelter in place" lockdown.

He used a pencil to scrawl what prosecutors called his "manifesto" on the sides of the boat. It was pocked with bullet holes and streaked with blood.

He wrote he was jealous that his brother had achieved paradise by dying like a holy warrior in the gunbattle with police. He asked God to make him a martyr, too.

Tsarnaev has pleaded not guilty, although his attorneys do not dispute that he participated in the bombings. Clarke asked jurors in her opening statement to keep their minds open to an alternative explanation.

The defense began its case with two witnesses called to offer scenarios that differ from the version of events offered by FBI witnesses. One focused on the the defendant's Twitter posts a year before the marathon, including mundane matters such as whether he should sleep in or get breakfast.

Another challenged the way the FBI used GPS points and store receipts to document the purchase of pressure cookers, BBs and ammunition -- allegedly by Tamerlan Tsarnaev.

The Arkansas House on Tuesday approved a religious freedom measure that mirrors the one Pence signed into law in Indiana -- sparking outrage from businesses, sports organizations and popular culture figures who said it opened the door to discrimination against gays and lesbians.

Hutchinson, a Republican in his first year in office, said Monday that he'd sign the measure -- but that was when lawmakers were still trying to find tweaks that ultimately eluded them.

"If this bill reaches my desk in similar form as to what has been passed in 20 other states then I will sign it," he said then.

The perils Hutchinson faces were made clear Tuesday morning when Pence insisted he'd "fix" Indiana's law to make sure it doesn't allow businesses like Christian florists or bakers to turn away gay and lesbian customers -- which the bill's conservative supporters had said was one of their chief goals.

"Was I expecting this kind of backlash? Heavens no," Pence said.

Following Indiana, Arkansas becomes the second of what could be a spate of states to add religious freedom laws to their books this year. There are 14 other states considering similar proposals this year, according to the National Conference of State Legislatures.

Advocates of the measures insist they're simply mimicking what the federal government did under President Bill Clinton, and what 19 other states had already done.

But the context has changed. The Supreme Court is poised to issue a ruling that could legalize same-sex marriage across the United States -- and social conservatives have come to view religious freedom laws as the next frontier in the culture clash over gay rights.

And Indiana's fight exposed another problem: Gays and lesbians lack the shield that a state anti-discrimination law that includes protections based on sexual orientation would offer -- and Pence has said he's not interested in changing that.

Making social conservatives' case harder is the intense opposition from business communities. In Arkansas, home-state giant Walmart was a leading critic of the religious freedom bill.

The other states where religious freedom bills have been introduced are Colorado, Georgia, Hawaii, Michigan, Montana, Nevada, North Carolina, Oklahoma, South Carolina, South Dakota, Texas, Utah, West Virginia and Wyoming.

Those efforts have stalled, though, in North Carolina and Georgia.

A Georgia bill hit a roadblock when a House member successfully amended anti-discrimination language into it.

And in North Carolina, Republican Gov. Pat McCrory has said he won't sign the measure into law, saying Monday in a radio interview that the proposal "makes no sense."

"What is the problem they're trying to solve?" McCrory said. "I haven't seen it at this point in time."